爲了能讓cisco交換的遠程連接對於賬號密碼的安全性有所提高，可以用ssh方式連接終端，但是很多出廠的交換機默認的ios是不支持ssh這個功能的，爲了能讓cisco交換機支持ssh，必須升級帶“K9”的IOS.下面是出廠cisco 3750G-24TS默認ios的截圖
3750交換機支持SSH需要12.1（11）EA1以上版本軟件。
emi是增強型多層鏡像，也就是對路由協議的支持更全；而smi是標準多層鏡像。
特性集共有三種：IP BASE、IP Services和Advanced IP Services。
- IP BASE：支持第2層轉發和基本的第3層路由，包括EIGRP stub模式。
- IP Services：包括IP BASE特性集，支持高級第3層路由，如OSPF和組播路由。
- Advanced IP Services：包括IP Services，支持IPv6功能。
解決方案步驟：
1. 從cisco官網下載ios
2. 升級ios
3. 配置交換機支持ssh
從cisco官網下載ios
打開cisco官網
也可以直接打開以下鏈接：
http://tools.cisco.com/support/downloads/go/Redirect.x?mdfid=282504484
會跳出登錄界面
未註冊的用戶根據註冊信息填寫就行，但有一點就是郵箱一定要填寫正確，因爲註冊後會發一份郵件到您的郵箱去激活纔可以使用
接下來登錄進去，選擇後綴帶SE版本就會自動鏈接其他頁面去了
跳轉下一個頁面如下，選擇要找交換機型號
跳轉下一個頁面如下，點解下載軟件
跳轉下一個頁面如下，選擇最新版本下載。但根據經驗的話，最好選擇最新版本後退一兩個版本。這裏我們選擇最新IOS版本，並下載帶“K9”字符的ios
……………………………………………………省略
跳轉下一個頁面如下
跳轉下一個頁面如下
這樣c3750-ipbasek9-mz.122-53.SE3.bin就下載來。後來發現！由於在應用中， cisco 3750G需支持其他一些路由協議。所以我這裏就以c3750-ipservicesk9-mz.122-50.SE3.bin爲升級版本IOS
提供一個非官網下載鏈接：
11.6 MB大小
CISCO Server TFTP 下載地址：
這裏以CISCO Server TFTP升級方式，如下圖
拷貝c3750-ipservicesk9-mz.122-50.SE3.bin
到TFTP目錄下面
升級ios
3750G(config)#interface vlan 1
3750G(config-if)#ip add
3750G(config-if)#ip address 192.168.100.2 255.255.255.0
3750G(config-if)#end
3750G#ping 192.168.100.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.100.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
3750G#dir
Directory of flash:/
3 -rwx 1754 Feb 5 2010 16:40:45 +00:00 config.text
4 -rwx 5 Feb 5 2010 16:40:45 +00:00 private-config.text
7 drwx 192 Mar 1 1993 00:07:31 +00:00 c3750-ipbase-mz.122-35.SE5
32514048 bytes total (22883840 bytes free)
3750G#delete/force(不再詢問確認) /recursive(刪除目錄下的子目錄和文件) c3750-ipbase-mz.122-35.SE5
3750G#copy tftp flash （從tftp下載ios）
Address or name of remote host 192.168.100.1 輸入tftp地址
Source filename c3750-ipservicesk9-mz.122-50.SE3.bin ios名稱
Destination filename [c3750-ipservicesk9-mz.122-50.SE3.bin]回車
Accessing tftp://192.168.100.1/c3750-ipservicesk9-mz.122-50.SE3.bin...
Loading c3750-ipservicesk9-mz.122-50.SE3.bin from 192.168.100.1 (via Vlan1):
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 12239852 bytes]
3750G#conf t
Enter configuration commands, one per line. End with CNTL/Z.
3750G(config)#boot system flash:c3750-ipservicesk9-mz.122-50.SE3.bin
設置啓動c3750-ipservicesk9-mz.122-50.SE3.bin爲新IOS
3750G(config)#exit
3750G#wr
*Mar 1 03:59:40: %SYS-5-CONFIG_I: Configured from console by consoler
Building configuration...
[OK]
3750G#reload
Proceed with reload? [confirm] 回車
*Mar 1 03:59:51: %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command.
Base ethernet MAC Address: 3c:df:1e:c4:a1:00
Xmodem file system is available.
The password-recovery mechanism is enabled.
Initializing Flash...
flashfs[0]: 501 files, 7 directories
flashfs[0]: 0 orphaned files, 0 orphaned directories
flashfs[0]: Total bytes: 32514048
flashfs[0]: Bytes used: 21870080
flashfs[0]: Bytes available: 10643968
flashfs[0]: flashfs fsck took 8 seconds.
...done Initializing Flash.
Boot Sector Filesystem (bs) installed, fsid: 3
done.
Loading "flash:c3750-ipservicesk9-mz.122-
50.SE3.bin"...@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
File "flash:c3750-ipservicesk9-mz.122-50.SE3.bin" uncompressed and installed, entry point: 0x1000000
executing...
Restricted Rights Legend
Use, duplication, or disclosure by the Government is
subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.
cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134-1706
Cisco IOS Software, C3750 Software (C3750-IPSERVICESK9-M), Version 12.2(50)SE3, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Wed 22-Jul-09 06:19 by prod_rel_team
Image text-base: 0x01000000, data-base: 0x02D00000
Initializing flashfs...
flashfs[1]: 501 files, 7 directories
flashfs[1]: 0 orphaned files, 0 orphaned directories
flashfs[1]: Total bytes: 32514048
flashfs[1]: Bytes used: 21870080
flashfs[1]: Bytes available: 10643968
flashfs[1]: flashfs fsck took 2 seconds.
flashfs[1]: Initialization complete....done Initializing flashfs.
Checking for Bootloader upgrade.. upgrading.. writing boot sectors..done.
The system will now restart
Boot Sector Filesystem (bs) installed, fsid: 2
Base ethernet MAC Address: 3c:df:1e:c4:a1:00
Xmodem file system is available.
The password-recovery mechanism is enabled.
Initializing Flash...
……………………………………………………………….中間省略
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 28 WS-C3750G-24TS-1U 12.2(50)SE3 C3750-IPSERVICESK9-M
說明升級成功了
Press RETURN to get started!
配置交換機支持ssh
3750G(config)# enable secret viong
3750G(config)#username viong password 123456
3750G(config)# line vty 0 4
3750G(config-line)#login local
3750G(config-line)#transport input ssh
設置讓cisco交換機支持SSH連接
也許就那麼幾個步驟！有點畫蛇添足寫這麼多。請別嫌棄我
但爲了規範點，還是辛苦點整理出來。
本文出自 “技術在於折騰” 博客，請務必保留此出處http://viong.blog.51cto.com/844766/282327